this study describes the morphology and arrangement of the cuticular structures of hyalella castroi gonzález, bond-buckup & araujo, 2006 and hyalella pleoacuta gonzález, bond-buckup & araujo, 2006, to identify specific characters that can be used in taxonomstudies of this genus. the entire cuticular surface of both species was examined by optical and scanning electron microscopy. the data obtained were compared with available information for other members of peracarida, mainly amphipoda and isopoda. five different types of cuticular structures, including 30 types of setae, four types of microtrichs, three types of pores, and some structures formed by setules and denticles were identified. the results were compared with other groups of gammarids, and peracarideans, such as thermosbaenacea and isopoda. the use of cuticular structures as a tool for taxonomic studies showed important results, not only at species level, but also at genus, and family levels.